Process for hardening copper



Patented Aug. 12, 1941 UNITED PROCESS FOR HABDENING COPPER Jonathan W. Sturtz, Cumberland, Md.

No Drawing. Application Serial No. 344,25

6 Claims.

The invention relates to a process and composition for hardening copper, and the object of the invention is to provide a process which not only hardens but which also toughens the metal, making it especially adaptable for use in bearings, journals, bushings, pump parts and other objects in which toughness as well as hardness of the metal is an advantage.

A further object is to provide such a process for treating copper in which the metal is made more dense or uniform in structure, obviating blow holes and similar internal defects in the metal.

A still further object is to provide a process for hardening copper by combining therewith cop- {uly 6, 1940,

per, phosphorus, salicylic acid, powdered pumice,

as follows:.copper, 4: lbs. or 128 parts; copper phosphorus, 1 oz. or 2 parts; salicylic acid, /a oz. or 1 part; powdered pumice, oz. or 1 part; and carbon, preferably in the form of graphite, /2 oz. or 1 part. v

Samples of some of the copper phosphorus which applicant has used in this process have been analyzed and found to contain about 85% copper and about 15% phosphorus.

As it is known that phosphorus added to copper has a tendency to harden the copper, it will be obvious to those skilled in the art that varying degrees of hardness may be obtained by not only varying the amounts of the several ingredients, as hereinafter stated, but by varying the phosphorus content of the copper phosphorus.

Although the i above proportions have been found in practice to give the most satisfactory results it should be understood that the inven-- tion is not limited to these exact proportions, but permits of variations in the amounts of the several ingredients used.

In carrying out the improved process the desired amount of copper is placed in a crucible or the like and brought to the melting point and while in molten condition the copper phosphorus preferably in solid cakes, and the salicylic acid and pumice, both in powder form are added to the molten copper and the mixture is stirred slightly for a short time until thoroughly mixed.

The mixture is kept in molten condition for about five to eight minutes at which time the crucible containing the same may be removed from the pit and carbon, preferably in the form of graphite, is added for the purpose of purifying the metal.

For this purpose the carbon or graphite may be added in solid form, preferably a piece of an electrode of the desired weight being used.

piece of electrode is introduced by means of a pair of tongs by which the carbon is pushed to the bottom of the crucible of molten metal and held there for a few minutes, approximately about 5 minutes being sufficient to entirely burn up the.

carbon. 1

The metal may then be poured and the resulting metal is very hard, tough and dense, and is, therefore, particularly useful for bearings, journals, bushings, pump p its and other parts of machinery where copper castings may be employed and which require hardness or toughness as well as density of the metal where machining of the parts is necessary.

It is well-known that phosphorus added in certain, proportions to copper has-a tendency to harden the copper, and it has been found by applicant that the addition of salicylic acid and pumice in proper proportions toughensjand solidifies the copper so that the same is not only hard, but tough and dense of structure so as to resist wear, thrusts and impact as well'as producing metal suitable for machining.

The addition of the carbon or graphite to the metal is primarily for the purpose of purifying the molten mixture which has been hardened and toughened and-solidified by theaddition of the other ingredients.

I claim: I

1. The process of hardening copper which consists in mixing with four pounds of copper in a molten state, one ounce of copper phosphorus, one-half ounce of salicylic acid and one-half ounce of powdered pumice.

2. The process of hardening copper which consists in mixing with 'four pounds of copper in a molten state, one ounce of copperphosphorus, one-half ounce of salicylic acid ,and one-half ounce of powdered pumice, and then stirring the molten mixture. r

sists in mixing with about 128 parts of the copper, while in a moltenstate, about two parts of copper phosphorus, about one part of salicylic acid and about one part of powdered pumice, and about one part of carbon.

3. The processof hardening copper which con- 4. The process of hardening copper which consmall amounts of copper phosphorus, salicylic acid and powdered pumice and then stirring the molten mixture.

6. The process or hardening copper which consists in mixing molten copper with relatively small amounts of copper phosphorus, salicylic acid and powdered pumice and then stirring the molten mixture and then adding a. small amount of solid carbon to the molten mixture.

JONATHAN W. STURTZ. 

